Specialty drugs grew 9.2%, compared with 9.7% in 2014, and generic drugs climbed 2.9%, down from the previous year's cost increase of 4.9%, according to the analysis.

The growth in prescription drugs prices — especially in the area of specialty drugs used to treat conditions like hepatitis C and multiple sclerosis — has weighed heavily on employers' total health care costs, prompting employers to implement such cost management strategies as prior authorization, step therapy and restrictions on quantities, several 2015 studies show.

“These new figures underscore growing concerns about the increasingly prohibitive costs of prescription medications — a matter that prompted extensive debate in 2015 among presidential candidates, congressional representatives, health care providers and pharmaceutical executives,” A.J. Loiacono, co-founder and chief innovation officer at Truveris, said in the statement. “Even as pressures mount, the trend of rising costs shows no signs of stopping, making it critical for consumers to take matters into their own hands to control their healthcare spending.”